The ultimately intention of knowledge management is to get the most income, it is necessary to measure the effect of knowledge management, thus the key problem of this study is how to evaluate the performance of knowledge management in High-tech Enterprise. Based on both case studies and model building, this paper analyzed the content and principle of the performance evaluation of knowledge management in High-tech Enterprise, and then established the evaluating index system of knowledge management performance and designed the evaluating method and steps. It gave the corresponding evaluation index weight by using expert evaluation method. Further, this paper made empirical research on the performance evaluation of knowledge management based on the fuzzy and comprehensive evaluation method. The results can explain how the performance is after knowledge management and put forward to views of rectification at evaluation results. The research of this paper provides essential theoretical method and tactical support for high-tech enterprises to implement effective knowledge management and enhance comprehensive competitiveness.